1) Field of the Invention
This invention relates to devices for cooling the body. Outdoor activities, particularly those participated in during the hotter times of the year, may lead to overheating, fatigue, excessive perspiring, and other related discomforts. It is known that application of water, cool compresses or other such cooling devices can relieve many of the symptoms related to overheating and help to prevent more serious consequences, such as heat stroke. The present invention addresses such concerns related to, or caused by, outdoor recreational or other leisure activities during warm weather where overheating is often a concern.
2) Description of Prior Art
All prior art in this particular field consists of relatively simple "home" remedies, the majority of which involve wrapping a moist piece of cloth, such as a towel, around the head or neck of the wearer to provide a cooling effect. While this approach may be moderately effective initially, the cooling effect is short-lived due to the rapid evaporation of the moisture from the towel or cloth.
Other cooling devices have been patented, all of which have been directed to therapeutic implementation using ice, and/or gels of various sorts which require freezing. Such devices are directed to the therapeutic cooling of certain body parts which have been injured in some way and require that the afflicted area be cooled to a significant degree. Therapeutic cooling requires that the temperature of the afflicted body area be significantly dropped (from about 35.degree. C. to about 5.degree. C.) for a period of at least fifteen minutes. This cooling usually relies on the high latent heat of fusion of water. Latent heat of fusion refers to the relatively large amount of heat required to melt ice. This results in the ability of the cooling device containing the frozen water (ice) to provide a relatively cold environment for a length of time sufficient to drop the temperature of the injured body part to the required extent to achieve therapeutic benefit. Such devices are disclosed in U.S. Pat. Nos. 3,545,230. 4,671,267, and 4,910,978.
Therapeutic cooling devices rely on the heat of fusion of water, in the form of ice, to provide the necessary cooling effect. The prior art discloses a number of configurations taking advantage of this property of water. One common feature of such devices is that they are comprised of a plastic or other vinyl-like envelope containing water or a water-containing gel-like material. In some inventions the envelope consists of plastic/vinyl envelope which is laminated to an outer material constructed from a woven or non-woven textile material. In any case, this envelope is essentially non-permeable to the free flow of water from inside the envelope to the outside.
The reliance of these therapeutic devices on the heat of fusion of water, that is the high heat capacity of the frozen water as ice, as well as the non-permeable nature of the container in which the water and/or gel is found, makes them unsuitable for the kind of recreational purpose for which the present invention is designed. The therapeutic devices must be exposed to very cold temperatures (below freezing) in order to lower the temperature of the water/gel sufficiently to provide a therapeutic benefit when used by the patient. Once exposed to the very warm conditions experienced in warm weather outdoor activities, the cooling effect rapidly dissipates and cannot be regenerated without returning the device to a freezer.
While several inventions have been patented disclosing devices for achieving a therapeutically significant drop in temperature at a specific location of an injury on the human body, these devices can be used only under restricted conditions and are wholly unsuited for cooling the body under conditions experienced while engaged in any of the many activities practiced out of doors in warm weather. Thus, a need exists for a simple, convenient device which can provide a sense of cooling relief to the wearer while engaged in any of the myriad forms of outdoor or indoor recreation.